s390/tape: Add missing destroy_timer_on_stack()

Otherwise we leak a tracking object when DEBUG_OBJECTS is enabled.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/tape_std.c

@@ -79,6 +79,7 @@ tape_std_assign(struct tape_device *device)
 	rc = tape_do_io_interruptible(device, request);
 
 	del_timer_sync(&timeout);
+	destroy_timer_on_stack(&timeout);
 
 	if (rc != 0) {
 		DBF_EVENT(3, "%08x: assign failed - device might be busy\n",